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So. Many. Wires.

Posted 2010.12.31 18.58 in Computers/Internet/Technology, Hobbies by Stephanie

The DIY Thermostat project hasn’t gotten as far along as I had hoped. Or, it has moved forward in leaps and bounds. Depends on how you measure progress, I guess.

I haven’t started building the finished project, it is still on the breadboard. However, I’ve expanded the breadboard to include all the working parts, i.e. the finished button layout, and the relays that will control the furnace and air conditioner.

I’ve also changed plans, in terms of the communications.

I was originally working with Bluetooth, and indeed had a working prototype with a bluetooth module. I wasn’t too happy however with the BT functionality. It was not that reliable, I found — as in, being able to ‘guarantee’ that I could connect to it every time, automatically, any time I tried. There’s that messy handshake business, with PIN numbers and stuff, and that seemed to be a hang-up.

Also, ultimately it would have been paired with my server which is Linux, and there seemed to be more issues there, getting the paired connection and the PIN numbers and blah blah blah. It was looking aggravating.

My plan-b was to use a different wireless scheme, the XBee modules. These looked attractive in that at the computer-end it would just be a usb-serial port, and would be always connected. However, there were some cost issues (It would have run about $100 for the modules etc. to achieve what I wanted) and again, no guarantee of 100% reliable connectivity.

So on to plan c. Good old safe, secure, and reliable ethernet. Getting from wireless to wired didn’t happen in one step. I was also dealing with the power requirements my Thermostat had. I didn’t want to have to constantly feed it batteries, and my design looked like I was going to need 3 or 4 AA batteries to fully power it. So I was already starting to accept that I would probably have to run some extra wires into the thing, to provide 5vdc.

With that on my mind, and looking at the communications options, I realized that I could solve both the power and comms issues with a single Cat5 line. Power over ethernet. I can use mode B, grab one of the unused pairs in the Cat5 cable, and pump the power in there, from my switch. Then at the thermostat, I just tap the power pair and run it through a regulator and hey presto, 100BaseT link, and power too!

Here’s the new version of the prototype, breadboarded with the relays, switches, and — yeah, that’s an ethernet port up there on top.

So the next step (again) is to start building all this into the finished project box; moving it off the breadboard and into the final package. Also, there’s some more coding to be done, to get the ethernet comms working right.

I can’t build a complete web server into it — not enough space left in flash or ram. I’ll create my own little thermostat protocol and then create a web interface for it on my home server. And the iPhone app that I will be creating. 😉

Rage Against the Wireless Machine

Posted 2010.07.14 12.11 in Computers/Internet/Technology by Stephanie

So this is my latest masterpiece, right?

I call it “Rage Against the Wireless Machine”. See, it’s supposed to symbolize the eternal struggle between network admins and the machines they must work with every day.

Rage Against the Wireless Machine - Click for Full Size

This particular piece is mixed-media, comprised primarily of fibreglass, copper, and plastic. Inspiration came to the artist during a discrepancy over IP addresses. The artist’s vision was realized through the expert use of a 16oz claw hammer. Size, approx. 6″ x 4″, excluding antenna. Currently on exhibition in an IT environment, where it may serve as an inspiration to staff, and a warning to equipment.

Linux Kernel for Eeepc 1008HA

Posted 2009.08.07 7.33 in Computers/Internet/Technology by Stephanie

I had a request this morning for my linux kernel that I’m using on my Eeepc 1008HA. This is a sub-notebook (aka “netbook”) computer by Asus, it’s very thin and light, though it sports a 10″ screen and a good-sized keyboard.

So on with the kernel info. I’ve been running a custom-built kernel since before I got the 1008; I have been rolling my own eeepc-specific kernel for over a year now, first for my 8G then the 1000, and now the 1008. As of this writing, the kernel version is 2.6.30.4. Essentially I’m downloading the generic “vanilla” kernel from Kernel.org and then applying my own config to it. The config is tweaked to include specifically what I personally want / need, and omits everything else. So fair warning: If you need a kernel that knows about nfs or ntfs or fatfs etc, this kernel won’t work ‘out of the box’ for you. Mucking around with the kernel is not something for total noobs to do, because it’s very easy to end up with a computer that doesn’t boot any more.

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